Lock-stitch sewing machine



Feb. 1 1927. I

N. F. HOPKINS LOCK STITCE SEWING MACHINE 2 Sheets-Sheet 3 Filed Jan. 10.. 1922 ham 7 mvzess gr 0 w m zh MMV Feb. 1,1927. 1,616,049

N. F. HOPKINS LOCK STITCH SEWING MACHINE Filed Jan. 10, 1 2 2 Sheets-Sheet 2 A a 22M $564, 54) Was Patented Feb. 1, 1927.

UNITED. STATES PATENT NATHAN HOPKINS; OF :RGGIQ'LAND, TILQEIrSSAChUSETTS, fiElEIG 'iil'OR .TO UNITED SHLOE FIvIACHINER-Y OOREORATION, OF .PATERSON, NEW? JEREJEY, A 'CGRFORATIGN 033 :NEW JERSEY.

.LOGK-STI'ICH :SEWTING. I fEAGHINIi-l.

Application-filed January'lOflSZZ. Serial No. 528,313.

The invention relates tolock stitch sewing machines such as are used inthe manufacture of shoes for sewing the outsoleto the welt of a welt shoe.

It has been found desirable in machines of this class to actuate'certain parts such as theneedle, awl, and take-up by constantly rotating cranks owing to the increased speed which may thus be secured. This manner of actuating the take-up, particularly in connection with a crank actuated needle,renders it diflicult to accurately control the delivery of thread to the various thread handling devices of'the stitch forming mech anism. An auxiliary take-up has heretofore been utilized to cooperate with the c'ank operated take-up in controlling the thread buthas no I proved wholly satisfactory due to complication ot'partsresulting in wear *andbreakage and also due to the failure under some conditions-and when operating with certain classes of thread to maintain the proper tension on the thread while being manipulated bythe stitch forming devices,particularlythe loop spreader and the hook or shuttle which carries the loop overthebobbin case for the locking thread. i

t is accordingly the object of thepresent inventionto provide for the accuratecontrol ofthe thread when operated on by a crank actuated take-up and to thatend it comprises the features of construction anr combination of parts hereinafter described and set forthin the claims.

In the accompanying; drawingsthe preferred form of the invention is shown applied to-=anoutsole stitching; machine having the same general construction and-mode of operation as the machine shown and described-in "Patent No. 1,1'69,909, dated February 1, 1916. Fig. 1 is a sectional elevation showing so much of the machine as is necessary to illustrate the application of the present invention thereto, Fig, 2 is a partial front elevation, Fig. 3 is a section on line 3-3, Fig. 1, and Fig. 4; is a detail of the auxiliary take-up.

The machine shown is provided with a work support 2, a presser foot 4, a crank actuated curved hook needle 6, a crank actuated awl 8, a looper 10, a thread finger 12, a loop spreader 14 a continuously rotating loop taking hook 16 and a thread pullott 18 and thread measurer20, all of which are constructed and actuated as inthe nrachine of said patent. The machine is also provided with rear and front thread locks 22 andQdcarried on opposite ends of a lever 26. The lever is szecuredto a rock shaft 28 which is rocked to alternately engage the locks with the thread through a second rock shaft 30 connected therewith by gear seg- 1nents32 and actuated by a cam 34 and cam lever 86 through a yielding connection partially indicated at 38.

The means for taking up theneedle-loop to set the stitch and for controlling the thread suppliedto the thread tinge-r, looper,

needle, loop spreader and rotary hookwhile for actuating theta ke-up or for actuating: thetakeaip and the needle does not altect the thread which is being operated on by the thread handling devices of the stitch forming mechanism. The thread acted on by these devices is drawn by them three h the tension as'required and suiticient'tensimi is therefore maintained on the thread to cause it to be raised by the loop spreader and passed aboutthe bobbin case by the rotary hook in: a certain and reliable manner without danger of the breakagewhich. frequently occurred in prior constructions due to the pulling o1": slack thread tln'ough the work by these devices and the consequent jan'uning of the thread between the hook and raceway. The constant tension on the. thread also secures a more uniform formation of the stitch and location of the lock than has heretofore been practical with constructions in which the needle loop is taken up and the stitch set by a crank operated take-up. The provision of the tension between the take-up and stitch forming devices also permits the use of a rigid or unyielding auxiliary take are up to cooperate with the crank actuated takeup with a resulting increase in the strength and durability of the auxiliary takeup mechanisn'i.

In the construction shown the take-up 40 is mounted on one arm 01 a lever l6 and is actuated from a continuously rotating crank 48 through a bell crank lever 50, one arm of which is connected by a link 52 to the take-up lever, and the other arm of which is connected by a link 54 with the crank. The auxiliary take-up 42 is mounted directly on a rigid arm 56 secured to a rock shaft 58. The rock shaft is provided with an arm 60 which is connected to one link of a toggle 62, the center joint of which is connected by a link Set with a cam operated lever 66. The tension ra is arranged close to the under side of the work and as shown comprises two disks mounted on the pivot stud 68 for the thread finger 12 and forced together by the spring 70.

The thread leads "from the wax pct 72, about a tension wheel '74, about a roll 76 with which the rear thread lock 22 cooperates, through the guides of the thread measurer 20, through a guide 78 on the plate which cooperates with the front thread lock 2 1-, over the take-ups a2 and 40, and then between the disks of the tension &4 to the thread handling devices of the stitch "forming mechanism. lhll'lfig the action of the thread finger, looper, needle, loop spreader and rotary hook the crank operated take-up 41:0 and the rigidly mounted takeup 44; are actuated to give up thread to each of these devices and to keep the thread in the system as nearly taut as practicable. This thread is drawn through the tension at as required by each of the thread engaging devices so that they are always acting upon a taut thread, thus insuring their uniform and reliable operation throughout the sewing.

While it is preferred to employ the specific construction and arrangement of parts in embodying the invention in the machine of the patent above referred to it will be understood that this construction and arrangement is not essential to the broader features of the invention and may be varied or modified as found desirable or best suited to the construction and mode of operation of the machine in which they are to be embodied.

lVhat is claimed is:

1. A lock stitch sewing machine having, in combination, stitch forming mechanism including a hook needle, a looper and a loop taker, a take-up, a continuously rotating crank for actuating the take-up, an auxiliary take-up, and a tension between the take-up and stitch forming mechanism through which the stitch forming mechanism draws the thread given up by the take-up.

2. A look stitch sewing machine having, in combination, stitch forming mechanism including a hook needle, a looper and a loop taker, a take-up, a continuously rotating crank for actuating the take-up, a rigid positively actuated auxiliary take-up, and a tension between the take-up and stitch forming mechansim through which the stitch forming mechanism draws the thread given up by the take-ups.

3. A look stitch sewing machine having in combination, stitch forming mechanism including a hook needle, a looper and a continuously rotating loop taker, a take-up, continuously rotating cranks for actuating the needle and take-up, a rigid positively act-uated auxiliary take-up and a tension close to the work through which the stitch forming mechanism draws the thread given up by the take-ups.

4. A lock stitch sewing machine having, in combination, stitch forming mechanism including a hook needle, a looper, a loop spreader and a loop taker, an oscillating take-upa continuously rotating crank tor actuating the take-up, and a tension through which the thread passes from the take-up to the looper.

5. A look stitch sewing machine having, in combination, stitch forming mechanism including a hook needle, a looper and a continuously rotating loop taker, a take-up, continuously rotating cranks tor actuating the needle and take-up, and a tension between the take-up and stitch forming mechanism through which the stitch forming mechanism draws the thread given up by the take-up.

NATHAN F. HOPKINS.

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